The pkg-config
program is used to retrieve information about installed libraries in
the system. It is typically used to compile and link against one or
more libraries. Here is a typical usage scenario in a Makefile:

program: program.c
cc program.c `pkg-config --cflags --libs gnomeui`

pkg-config retrieves information about packages from special metadata
files. These files are named after the package, with the extension .pc.
By default, pkg-config looks in the directory /usr/freeware/lib32/pkgconfig
for these files; it will also look in the colon-separated list of
directories specified by the PKG_CONFIG_PATH
environment variable.